Accidental Discoveries

You know how some of the greatest inventions come about by accident, like Penicillin or Teflon? Does that same thing happen with foods too? 'Cause the guy who invented prune juice couldn't possibly have been thinking about juicing a dried fruit, right? I just hope that's not the same with the milk that I just put in my cereal, because I'd hate to imagine what was going on when that was 'discovered' if it was an accident.